The Victorian Electoral Commission (VEC) has told a parliamentary inquiry there should be a review of legislation covering electoral campaigning on social media.

The Victorian Parliament's Electoral Matters Committee is investigating the impact of social media ahead of the state election in November.

The committee held public hearings in Melbourne today and in its submission to the inquiry, the VEC said there was a need for current legislation around electoral campaigning to be reviewed.

"It could be argued that Victoria's current legislation reflects an internet environment only - due to the period in which it was drafted, which pre-empted the rise of social media," the submission said.

The VEC also said social media has made it more difficult for the commission to determined what messages were authorised by party headquarters.

It said the issue of authorising messages on social media, particularly on Twitter, is a grey area.

"There is some difficulty in authorising tweets due to Twitter's limit of 140 characters," the submission said.

"Clarification of authorisation requirements where word limit restrictions apply could assist the administration of laws in this regard."

The VEC said the internet and social media could make it easier to track down people who breach electoral regulations.

"It is typically easier to identify and follow up authors online than it would be to remove unauthorised leaflets and identify the author resulting from a rogue, anonymous letter drop," the submission said.

But it said attempts to track down breaches by anonymous social media users could be time-consuming, particularly if the user was outside of Victoria.

Concerns over Google AdWords

The inquiry is also examining the use of Google AdWords in electoral advertising.

AdWords allows ads from paid sponsors to appear on Google searches based on a particular keyword.

Often the ads will link to a website that is a competitor of the original subject of the Google search.

The VEC pointed to an example in the 2010 election where an anonymous advertiser placed potentially defamatory ads relating to a candidate.

The ad linked back to the Australian Greens website, but the Greens complained they had not placed the advertising.

Google complied with the VEC's request to take down the ad, but would not provide the identity of the person who placed it.